Gargalesis (the kind that makes you giggle and squirm) and knismesis (the unnerving or irritating sensation like a feather brushing softly over your skin, also known as light-touch tickling) are the two types of ticklishness.
There are a few ideas as to why the ticklishness that makes you laugh occurs:
People connect through it. When a mother tickles her child, the child laughs, the mother grins, and the two experience joy together. Similar to adults, children who like tickling one another may become close. (However, teasing can also be a type of bullying.) Tickling can function as a form of sexual foreplay among adults. (However, some people find tickling uncomfortable and detest it.)
Ticklishness protects weak spots. It is believed that our response to tickling around the armpits and belly is a protective reflex. These are the top ticklish areas. Since the hands and face are more exposed yet not extremely ticklish, there are some holes in this argument.
The urge to rub the area that arises with light-touch tickling could be another example of a protective reflex. Therefore, if an insect is lightly tickling you while crawling on you, your natural instinct is to brush it off in order to prevent more harm.
How come you can't tickle yourself? Again, there are no facts that support the claim. One theory, however, is that being tickled while laughing necessitates being unaware of its impending arrival. According to studies, when people are blindfolded and uncertain of where or when they will be tickled, they laugh harder.
